JPH0540298Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a diesel engine used in combine harvesters, tractors, etc., which easily and reliably drains the air in the fuel strainer using the suction action of the fuel supply pump, and also prevents fuel from scattering. The present invention relates to an air bleed device for a fuel strainer that can be removed without causing leakage.

Conventional technology Conventionally, diesel engines have been widely used in mobile agricultural machines such as combines and tractors, but their fuel tanks are designed to facilitate refueling and lower the center of gravity of the machine to improve stability. ,
They are often located below the driver's seat floor or below the chassis.

In vehicles with a fuel tank installed at a low position like this, it is common for a fuel pump to supply fuel from the fuel tank to the injection pump through a fuel strainer, and while the air in the fuel strainer can be easily bled by opening the air bleed valve at the top of the fuel strainer using the fuel pumping action, the fuel supply pump is placed in adverse conditions where it is prone to malfunction due to dust, water, etc., because it draws in unfiltered fuel. Therefore, in order to protect the fuel supply pump, it is advisable to install a fuel strainer between the suction side and the fuel tank, but since fuel only moves by suction within the fuel strainer, it is difficult to bleed the air that has accumulated above it using the action of the fuel supply pump, and so a complicated separate means must be taken to bleed the air from the fuel strainer.

In view of these circumstances, the present invention has been developed to remove air accumulated in the upper part of the fuel strainer by the suction action of the fuel supply pump, even if the fuel strainer is installed between the suction side of the fuel supply pump and the fuel tank. Therefore, it is an object of the present invention to provide a device that can be easily and reliably removed.

Problems to be Solved by the Invention The present invention, as a technical means to achieve the above object, provides an air bleed device for a fuel strainer in a diesel engine that connects the fuel tank to the fuel strainer and is injected by a fuel supply pump. In a diesel engine fuel system, which consists of a fuel supply route that supplies fuel to the fuel pump, and a fuel return route between the discharge side of the fuel supply pump and the fuel tank, a filter and a They are communicated via an on-off valve.

Function The air bleed device for a fuel strainer in a diesel engine according to the present invention communicates between the upper part of the fuel strainer and the suction side of the fuel supply pump via the filter and the on-off valve. The air accumulated in the upper part of the fuel strainer is reliably removed by the suction action of the fuel supply pump. Even if some of the fuel is sucked during this air bleeding, the fuel passes through the filter and is purified, and then joins the fuel supply path by the fuel supply pump, so that no fuel scatters or leaks.

Example Embodiments of the present invention will be described with reference to the drawings.

Fig. 1 shows the fuel system of a diesel engine, in which 1 is a fuel tank, 2 is a fuel strainer, 3 is a fuel supply pump, and 4 is an injection pump, which connects the fuel tank 1 to the fuel strainer 2. A fuel supply path 5 is configured to supply fuel to the injection pump 4 via the fuel supply pump 3.
An injection nozzle 6 is connected by a high-pressure pipe 7 to the injection nozzle 6 . Further, a fuel return path 8 is provided between the discharge side of the fuel supply pump 3 and the suction side of the injection pump 4 and the fuel tank 1.
Reference numeral 9 denotes an oil feed pipe from the fuel tank 1 to the fuel strainer 2, and 10 an oil feed pipe from the fuel strainer 2 to the fuel supply pump 3. As shown in FIG. 2, the fuel strainer 2 has an airtight strainer tank 11 divided into an outer chamber 13 and an inner chamber 14 by a filter 12, and includes an oil pipe on the fuel tank 1 side. 9 is connected to the outer chamber 13, and an oil feed pipe 10 on the side of the fuel supply pump 3 is connected to the inner chamber 14.

On the other hand, a filter 15 and an on-off valve 1 are connected between the upper part of the fuel strainer 2 and the suction side of the fuel supply pump 3.
6, the air bleed passage 1 in the upper part of the fuel strainer 2 is connected to the air bleed pipe 17, 18 through the
9 is formed, and 20 is an opening/closing knob for the opening/closing valve 16. Air bleed pipe 18 and oil feed pipe 9
is connected to by a three-way joint 21. In addition,
The filter in the air bleed path 19 may have a simple structure in which a sponge or the like is provided at the open end of the air bleed pipe 17 inside the fuel strainer 2. The on-off valve 16 is
In addition to the opening and closing mechanism 20, a push-type mechanism, an electromagnetic mechanism, etc. may also be used.

In the device configured as described above, when the fuel supply pump 3 is started, fuel enters the outer chamber 13 of the fuel strainer 2 from the fuel tank 1 via the oil feed pipe 9, and the fuel passes through the filter 12 and enters the inner chamber. Room 1
4, the fuel is sucked into the fuel supply pump 3 via the oil supply pipe 10, and is supplied from the fuel supply pump 3 to the injection pump 4. The fuel pumped to the injection nozzle 6 by the injection pump 4 is injected into the combustion chamber.

To remove the air accumulated in the upper part of the fuel strainer 2, open the on-off valve 16 after starting the fuel supply pump 3. , and is sucked and removed by the fuel supply pump 3 through the air vent pipe 18. Then, the sucked air is sent from the fuel supply pump 3 to the fuel tank 1 via the fuel return path 8, and is separated from the fuel and released. When air bleeding is completed, the on-off valve 16 is closed so that fuel is supplied only from the fuel supply path 5 via the fuel strainer 2.
Incidentally, during the above-mentioned air bleeding, fuel may be sucked into the air bleeding path 19, but even in this case, the fuel passes through the filter 15, so unfiltered fuel is included in the fuel supplied to the fuel supply pump 3. There is no risk of anything getting mixed up. Moreover, since all of the fuel sucked into the air bleed path 19 is sucked into the fuel supply pump 3, there is no chance of the fuel scattering or leaking as a result of air bleed.

In the example shown in FIG. 2, the diameter of the air bleed pipe 17 is smaller than that of the oil feed pipe 9 that sucks fuel into the fuel supply pump 3; If the diameter is larger than that of the oil feed pipe 9, the air suction resistance by the fuel supply pump 3 will be reduced, so that air can be removed quickly and completely.

FIGS. 3 and 4 show an embodiment in which air bleeding is automated in the apparatus shown in FIGS. 1 and 2. That is, in this embodiment, instead of the on-off valve 16 of the air vent path 19, an automatic on-off valve 2 that allows air to pass through but shuts off fuel is used.
2, and a valve 23 that is manually opened and closed is interposed in the fuel return path between the discharge side of the fuel supply pump 3 and the fuel tank 1. The other configurations are the same as those in FIGS. 1 and 2. The automatic opening/closing valve 22 is provided with a float-shaped valve body 24 whose specific gravity is higher than that of air and lower than that of fuel.

In this embodiment, when the fuel supply pump 3 is started, its suction action also extends to the air vent path 19, so air from the upper part of the fuel strainer 2 is sucked in. In this state, the valve body 24 does not float up, and the automatic opening/closing valve 22 remains open to bleed air. When the air bleeding is completed, the fuel is sucked up and the valve body 24 floats up, and the automatic opening/closing valve 22 is closed to block the outflow of fuel. Note that if the valve 23 between the discharge side of the fuel supply pump 3 and the fuel tank 1 is closed when air bleeding is completed, wasteful reflux of fuel by the fuel supply pump 3 can be eliminated and the load on the fuel supply pump 3 can be reduced. It can be reduced.

5 and 6 illustrate a carp harvester equipped with a diesel engine. 25 is a pre-processing section, 26 is a driver's seat, 27 is a paddy tank, 28 is a paddy discharge port, and 29 is a paddy receiving floor. It is designed to be stored in a bag 30. 31
32 is a straw processing section, 32 is a blower fan, and 33 is a worker's grip pipe provided on the front side of the paddy tank 27. This grip pipe 33 is connected to the blower fan 32, and a large number of air holes are provided on the underside of the pipe. Air is vigorously ejected from the ejection hole to form an air curtain between the paddy discharge port 28 and the worker, thereby protecting the worker from dust.

Effects of the Invention As described above, the present invention provides a fuel supply path for supplying fuel from a fuel tank to an injection pump via a fuel strainer and a fuel supply pump, and a fuel supply path between the discharge side of the fuel supply pump and the fuel tank. In a diesel engine fuel system consisting of a return path, the upper part of the fuel strainer and the suction side of the fuel supply pump are communicated via a filter and an on-off valve, so the fuel supply pump is started when the engine is started. By simply opening the on-off valve between the upper part of the fuel strainer and the suction side of the fuel supply pump, the air accumulated in the upper part of the fuel strainer can be completely removed by the suction action of the fuel supply pump. Even if a portion of the fuel is sucked in, the fuel is purified by passing through the filter and then merged into the supply path by the fuel supply pump, which has the effect of completely eliminating fuel scattering and leakage caused by air removal. It is something.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a fuel system diagram of a diesel engine, Fig. 2 is a sectional view of its fuel strainer and its air bleed path,
Fig. 3 is a fuel system diagram of a diesel engine showing another embodiment, Fig. 4 is a sectional view of its fuel strainer and air bleed path, Fig. 5 is an overall side view of the combine, and Fig. 6 is a part of it. FIG. 1...Fuel tank, 2...Fuel strainer, 3
... Fuel supply pump, 4 ... Injection pump, 5 ... Fuel supply path, 6 ... Injection nozzle,
8... Fuel return path, 15... Filter, 16...
...Opening/closing valve, 19...Air vent path, 22...Automatic opening/closing valve, 23...Valve, 24...Float-shaped valve body.

Claims (1)

[Scope of utility model registration request] In a diesel engine fuel system, the fuel system includes a fuel supply path that supplies fuel from a fuel tank to an injection pump via a fuel strainer and a fuel supply pump, and a fuel return path between the discharge side of the fuel supply pump and the fuel tank. An air bleed device for a fuel strainer in a diesel engine, characterized in that the upper part of the fuel strainer and the suction side of a fuel supply pump are communicated through a filter and an on-off valve.